Self-opening die-holder



3: n M 3? 524/ "E July 13, 1937. G. H. COTE 2,087,084

SELF OPENING DIE HOLDER Filed April 8, 1935 2 Sheets-Sheet l 36 H QjNVENTOR July 13, 1937. HICOTE 2,087,084

SELF OPENING DIE HOLDER Filed April 8, 1935 2 Sheets-Sheet 2 INVENTOR ORNEY Patented July 13, 1937 UNITED STAT PATENT OFFICE SELF-OPENING DIE-HOLDER George H. Cote, Bridgeport, Conn.

Application April 8, 1935, Serial No. 15,247

16 Claims.

provement on that shown in Patent No. 1,316,619,

granted September 23, 1919.

In said patent, the button die is split into two parts, and these are carried by jaws pivoted on a common center so as to open and close. The jaws are biased to normally open and are permitted to open when the jaws and the jaw carrier move longitudinally of the head on which they are mounted so that the dies will disengage the screw being out and permit quick withdrawal of the die holder from the work. To return the jaws to closed position, a camming device is provided adjacent the common pivot points of the jaws.

According to the present'invention, the jaws are pivoted at diametrically opposite points, and projecting portions of the jaws extend through slots in a housing therefor so that the jaws may 3 he opened and closed by rotation of the housing relative to the jaw carrier, the housing being biased for rotation in jaw-opening direction and being held against such rotation until it is moved longitudinally of the head. This arrangement permits the die holder to be substantially inclosed and the jaws to be moved to closed position as a result of rotation of the housing.

By having the jaws pivoted at diametrically opposite points, parallel separation of the dies is effected, and, if due to any irregularity in the die or holder the portions of the die, nearest the pivot of the jaws come together closer than the other portions, they will nevertheless enJgag-e diametrically opposite points on the rod being threaded and thus tend to balance each other. This arrangement also permits the depth of cut to be regulated by adjusting the means control-,

ling the normal closed position of the jaws.

An object of the present invention is the provision of the housing in such a way as to limit the axial movement of the jaws relative to the jaw holder and take up any wear which may occur. This means, acting as it does upon both jaws, prevents one jaw from being advanced beyond the other jaw and causing cross-threads to be cut on the rod. This is a particularly important advantageous feature when it is remembered that the jaws are opened as a result of the jaw holders being advanced through the medium of the dies while the head is held from advancing.

A further feature of this invention is the provision of improved means for resiliently holding the jaw carrier against axial movement'relative to the head and for locking the jaw carrier and its housing against arcuate movement until the axial movement is produced.

A still further feature of this invention is the provision'of means for adjustably mounting the head on the flange of the shank so that the head and jaw carrier carried thereby may be made concentric with the spindle and rod, and thus insure a true and accurate cut on even extremely small and fine pitch screws.

A still further feature of this invention is the provision of means in the shank of the die holder for permitting the die holder to yield when the end of the rod engages the dies; and, a further feature the provision of means whereby the extent of movement permitted by this yielding means may be maintained and varied by an adjustable device at the end of the shank, and if desired, bya further adjustment the relatively movable parts may be fixed against such movement. 7

Another feature of this invention is the provision of improved means for holding the die securely and tightly in place and yet permitting the threading operation to continue close to a shoulder or head on the screw being out.

Other features and advantages will hereinafter appear.

In the accompanying drawings which illustrate one form of this invention, that at present preferred- Figure l is an end view of the die holder assembled, showing the split button die in operative position thereon.

Fig. 2 is a side view of the die holder shown in Fig. l, with the end portion of the shank broken away, the die jaws being in closed position.

Fig. 3 is a view similar to Fig. 2, but showing the parts in the position which they assume when the jaw. carrier and housing have been moved axially and rotated to open the jaws.

Fig. 4 is a longitudinal sectional View of the die holder of the present invention.

Fig. 5 is a transverse sectional view taken on the line 55 of Fig. 4.

Fig. 6 is a similar view, but showing the die jaws in open position.

Fig. '7 is an exploded view showing a one-half button die and the clamp for holding it to the jaw holder, and the screw for holding the clamp to the die jaw.

Fig. 8 is a transverse sectional View taken on the line 88 of Fig. 4.

Fig. 9 is a transverse sectional view taken on the line 99 of Fig. 4.

Fig. 10 is a transverse sectional view taken on the line lB-iil of Fig. 4.

Fig. 11 is a view similar to Fig. 4, but showing the jaw carrier moved axially and about to be permitted to rotate.

Fig. 12 is a view like Fig. 11, but showing the positions of the parts after the jaw carrier and its housing have been permitted to rotate to open the jaws and release the screw, and showing the parts in the positions they assume after the jaw carrier has moved axially toward the shank.

Fig. 13 is an exploded view showing the main portions of the die holder of the present invention.

Figs. 14 and 15 illustrate a modification of the means for holding the half-button dies on the jawsFig. 14 being a section similar to Fig. 5, and Fig. 15 showing the die assembled on the aw.

As shown in the accompanying drawings, the die holder has a shank 28 adapted to be secured in a turret or other head 2! (shown in dot-anddash lines in Fig. 4), of a screw machine or the like. The shank has a flange 22 provided with slots 23 at diametrically opposite points to receive studs 24 threaded in a head 25 to clamp the head to the flange.

The head 25 has a central hole 26 in which a sleeve or projection 21 on a jaw carrier 28 extends. As shown, the hole 26 and the projection 2! are circular, and this is done for convenience in manufacture. The hole 26 and projection 21 may have any suitable shape, so long as there is maintained a sliding fit so that the jaw carrier may be moved axially of the head 25.

The jaw carrier 28 and head 25 are coupled for rotary movement together by screws 29 located in cavities 38 in the head 25 and threaded in holes 3! in the jaw carrier 28. Between a head 32 of each screw 29 and a bottom 33 of the cavity there is located a compression spring 34 tending to pull the jaw carrier against the face of the head 25 and maintain it yielding in that position, as shown in Figs. 4 and 12.

The jaw carrier, in the form of the invention herein illustrated, is provided with a pair of studs 35 projecting from its face, and on each of these studs there is pivotally mounted a die jaw 36.

Each jaw is provided with a segmental recess 31' in which a half button die 38 is located so as to lie on a flange 39. The latter has a. pin 48 against which the edge of a one-half button die may be placed to locate it in proper position in the recess 31 and to prevent arcuate movement of the die when cutting a thread. The recess 31 is so proportioned that the outer face of the die is substantially flush with the outer face of the jaw 36. To hold the die in the recess, there is provided a clamping piece 4| having an overhanging flange 42 which engages the outer face of the die and holds the die between itself and the flange 39. The jaw 36 has a slot 43 in which the clamping piece 4| lies, so that, except for the overhanging portion 42, it is also flush with the outer face of the jaw 36. The overhanging portion 42 has a recess 44 in which lies a head 45 of a screw 45 which is threaded in a hole 4'! in the jaw to draw the clamping piece 4i against the die 38 and lock it in that position.

By having the studs 35 on the jaw carrier diametrically opposite each other, the jaws 36 may swing away from each other with substantially parallel motion, and the ends of the dies may be provided with arms 48 by which the jaws may be moved toward and from each other by means mounted to rotate about the axis of the die holder.

For the purpose of enclosing the jaws and jaw carrier and to control the movements of the jaws in opening and closing directions, the device of the present invention is provided with a housing generally indicated by the reference numeral 49. This housing includes a cap 50 having diametrically opposite slots 5| through which the arms 48 of the jaws extend and an end flange 52 adapted to engage the outer faces of the jaws 36.

The housing 49 also includes a locking ring 53,

the internal diameter of which is such that it has a rotating fit or bearing on the periphery 54 of the jaw carrier 28. The external diameter of the ring 53 is such that it fits into the cap 50 and it has a flange 55 fitting against a shoulder 56 on the cap. The housing also includes a cap ring 5'! which has a flange 58 engaging the flange 55 of the locking ring 53, and the cap ring has internal threads engaging external threads on the cap 50.

The main function of the locking ring 53 is to hold the housing against rotation relative to the head 25 when the jaws are in closed or operative position, as will be pointed out below, but it also serves the function of covering the periphery of the jaw carrier 28 which, in the form of the invention herein illustrated, carries the means for normally urging the jaws to open position.

This means comprises a pair of springs 59,

each located in a recess 58 in the periphery of the jaw carrier 28, as shown in Fig. 13. Each spring 59 engages a shoe 6i slidably mounted in the recess 60 and tending to move arcuately about the axis of the jaw carrier and other parts.

The shoe 8| has a threaded hole aligning with a hole 62 in the locking ring, and through these holes there extend pins 53 and 64, and these extend to the exterior of the housing through slots in the cap 59.

It will thus be seen that the cap 58, ring 53 and cap ring 51 are coupled together to move as one when the pins 63 and 54 are in place, and that these move on the periphery of the jaw carrier. and the arms 48 of the jaw extending through the slots 5i, rotation of the housing relative to the jaw carrier will cause the jaws to open or close, depending upon the direction of rotation.

As shown in Figs. 4, l1 and 12, the outer edge of the locking ring 53 is clear of the jaws 3G, and hence the cap ring being screwed on the cap will cause the jaws to be drawn toward the face of the jaw carrier by the overhanging flange 52 on the cap. By this adjustment. the freedom of movement of the jaws bodily on the pins 35 may be controlled and, by simply adjusting the cap ring, great or little freedom of movement may be permitted, and any wear of the flange 52 on the surface of the jaw carrier by the jaws can be compensated for.

The means for determining the normal closed position of the jaws, for locking the housing against relative rotating movement after being moved longitudinally or axially, and holding the The latter being relatively stationary housing and the jaw carrier in the position to which it is moved longitudinally until the housing is again rotated, is provided by an adjusting ring 66. This is mounted on a reduced annular portion 61 on the head 25, and has at one side two diametrically opposite lugs 68, 68a extending. into slots 63 in the head. It is by means of these lugs 68 that the adjusting ring may have its position on the head 25 controlled.

As shown in the accompanying drawings in Fig. 10, this is accomplished by a screw Til threaded in one or" the lugs 68 and lying in a circumferential groove ll on the periphery of the head 25. When the screw is put in place, movement of the locking ring longitudinally or axially is prevented. The other lug 68a is provided with recesses on its opposite surfaces each adapted to be engaged by an adjusting screw it extending through the head. By loosening one screw '52 and tightening the other, the adjusting ring 65 may be rotated and locked in adjusted position relative to the head. At the other side of the adjusting ring, there is a pair of lugs i3 which normally fit in notches l t in the locking ring 53. This is the normal, closed, jaw thread-cutting position of the die-holder, see Figs. 2 and 4.

When the thread has been cut as far as desired and the turret has stopped advancing, the thread cut on the rod, such as the rod in 11, continues to draw the jaws, jaw holder and housing toward the left, as indicated by the arrow in Fig. 11. This movement removes the lug- F3 from the notch 14 in the locking ring and allows the locking ring, cap and cap ring to be rotated under the influence of the springs 59 until the relative positions of the parts are as shown in Fig. 3. In this movement of the housing relative to the jaw carrier, the jaws are opened (Fig. 12) and remain in this position while the turret is being retracted. Upon returning to normal out-of-the-way position, or at some later time, the housing is rotated counterclockwise, as viewed in Fig. 6, by suitable means provided in the path of the pin 64, which, for this purpose, is elongated and may be available for engagement.

During this time, the lug 13, being out of the notch M, holds the jaw carrier, jaws and housing axially advanced relative to the head and the springs 34 under compression. When the housing is rotated from the Fig. 3 to the Fig. 2 position, the lug 13 is again brought opposite the notch 'M and the springs 34 act to draw the jaw carrier and jaws to the right and into normal thread-cutting position.

It will be seen that by adjusting the ring 68 around the head 25, the position of the housing rotatably around the axis of the device may be varied, and since this movement of the housing controls the opened and closed jaws, the jaws and the die carried thereby may be moved closer to and farther from the work by adjustments of the screws 12.

Frequently the work is not concentric with the axis of the die-holder, thus causing the thread to be improperly cut. To obviate this difficulty, the slots 23. through which extend the screws 24 for holding the head 25 to the flange 22 are made slightly oversize and are radial. Thus, when the operator finds that the die head and the work are not concentric, he merely loosens the screws 24 and adjusts the head and the parts carried thereby to make it concentric and then fastens the screws 24 again. This is an extremely important feature of the present invention.

Sometimes it is required that the die hold yield somewhat upon the dies engaging the end of the Work, such as the rod 15 For this purpose, the shank 2!], according to the" present invention, is made of two pieces, an outer portion or sleeve 28a and an inner portion Mb. The inner portion 205 may be integral with the flange 22 if desired and the outer portion is mounted to slide on the inner portion, although it is held against rotation relative thereto by a spline l6 and a key 57. The purpose of providing the shank 2B in two parts is to permit the outer part or sleeve 26a to be held against axial movement by screws l8 of the turret head 2!, while the inner part 201) may axially slide relatively thereto. To resiliently hold the parts against such movement, however, there is placed between the parts 26a and 29b a compression spring l9, one end of which engages a shoulder 80 on the part a and the other end of which engages a nut 8| threaded on the part 20b. The nut (ii may, as shown in Fig. 4, be so adjusted that the outer end 82 of the part 28a engages the head of the nut 8!, while the inner end 83 of the part 22a engages the flange 22, thereby holding the parts 26a and 2% against relative longitudinal movement. When the nut 3! is unscrewed from the inner part 2%, limited movement, depending upon the distance between the end 82 and the head of the nut, is permitted, but then only upon the compressicn of spring E9. The head of the nut 8i preferably extends beyond the end of the part 280. so that it may be easily adjusted with a suitable wrench.

It will thus be seen that by adjusting the nut 8i on the part 2%, the extent of relative movement between the die-holder and turret head may be varied within limits and such movement may be prevented entirely.

So that a long thread may be placed. on the work, such as the rod 15, the jaw carrier 28, head and inner part 2% of the shank are all made hollow, the size of the hole being greater than the largest diameter rod which may be used with that particular die-holder.

To assist in discharging the chips from the dies and housing, the cap is provided with a pair of oppositely disposed holes 84, (see Fig. 6).

A modification of the means for mounting the die segments is shown in Figs. 14 and 15. In this form of the invention, the clamping plates ll and the screws 45 are dispensed with and instead each jaw 36 is provided with a pin 90 near the stud 35. This pin extends in toward the axis of the device. At the free end of the jaw there is provided a locking pin 91 in the form of a screw having a tapered head 92.

The die segment 38a, in the form of the invention shown in Figs. 14 and 15, has one edge portion 93 ground so as to incline outwardly and toward the axis of the device when mounted in the recess of the jaws 36 as shown in Fig. 15. The other edge portion 94 is ground so that when the set screw 9! is screwed into the end of the jaw 36, the tapering end 92 thereof will crowd or push the die segments 3% against the pin 96. This, due to the cam surface 93, will cause the die segment 38a to be drawn tightly against the flange 39 of the jaw. Since the edge 94 has itself a slight bevel 95 (see Fig. 14), pressure of the tapered screw thereon will cause the adjacent portion of the die segment 38a to be pressed firmly against the flange 39.

With this arrangement, there is nothing projecting beyond the face of the die to limit the movement of the die and die-holder toward the work, and thus permitting the cutting of threads close to a shoulder having a diameter fitting within the flange 52 of the cap 49.

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.

Having thus described the invention, what is claimed as new and for which it is desired to obtain Letters Patent, is:-

1. A self-opening die holder including a jawcarrier; a plurality of jaws pivotally mounted on said carrier, each having a radial lug; means on each jaw for holding one half of a thread cutter; and means including a housing for said carrier and jaws and resiliently biased to arcuately move relative to said carrier, said housing having slots engaging said radial lugs on the jaws for swinging said jaws on their pivots to open the same when said housing and carrier are rotated relatively in one direction.

2. A self-opening die-holder including a jawcarrier; a plurality of jaws pivotally mounted on said carrier, each having a slide bar; means on each jaw for holding a thread cutter; a housing for said jaw-carrier and jaws having guide-ways in which the slide bars of the jaws are disposed, the housing being arcuately movable relatively to said carrier for swinging the said jaws on their pivots to open the same; circumferential slots in said carrier; springs in said slots; and shoes in said slots engaged by said springs and connected to the housing normally to urge the latter in jaw-opening direction.

3. A self-opening die holder including a disk; a pair or" jaws pivotally mounted on the disk at diametrically opposite points thereon; means on each jaw for holding one half of a split button die; a radial lug on each jaw; and means, including a cap, provided on its periphery with slots to receive and operatively engage said lugs and resiliently biased to arcuately move relative to said disk for swinging said jaws on their pivots to open the same.

4. A self-opening die-holder including a jawcarrier; a pair of jaws pivotaily mounted on said carrier; means on each jaw for holding one-half of a split button die; a housing for said jaw-carrier and jaws having operative connections with said jaws and being arcuately movable relative to said jaw-carrier for swinging the said jaws on their pivots to open the same; resilient means between the housing and the carrier to normally urge said housing in jaw-opening direction; a shank; a head thereon and fixed to rotate therewith and supporting said jaw-carrier; a ring movable relatively to said head; and means carried by the ring and engaging the housing for normally locking the ring and the housing against relative movement to restrain said housing from moving in jaw-opening direction.

5. A self-opening die-holder including a jawcarrier; a pair of jaws pivotally mounted on said carrier; means on each jaw for holding one-half of a split button die; a housing for said jawcarrier and jaws having operative connections with said jaws and being arcuately movable relative to said jaw-carrier for swinging the said jaws on their pivots to open the same; resilient means between the housing and the carrier to normally urge said housing in jaw-opening direction; a shank; a head thereon and fixed to rotate therewith and supporting said jaw-carrier; a ring movable relatively to said head; means carried by the ring and engaging the housing for normally locking the ring and the housing against relative movement to restrain said housing from moving in jaw-opening direction; and means for setting the ring in various adjusted positions relatively to the head to adjustably fix the normal closed positions of the jaws.

6. A self-opening die holder including a disk; a pair of jaws pivotally mounted on the disk at diametrically opposite points thereon; means on each jaw for holding one half of a split button die; a radial lug on each jaw; a cap provided on its periphery with slots to receive and operatively engage said lugs and arcuately movable relative to said disk for swinging said jaws on their pivots to open the same; springs between the disk and cap to normally urge said cap in jaw-opening direction; a shank; a head thereon and fixed to rotate therewith and supporting said disk; and a ring connected to said head and having a lug engaging a notch in the cap for normally restraining said cap from moving in jaw-opening direction, said disk and cap being axially movable away from said head and shank to separate said lug and notch and permit rotation of said cap in jaw-opening direction when said cap and disk are moved axially relative to said head and shank.

'7. A self-opening die holder including a disk; a pair of jaws pivotally mounted on the disk at diametrically opposite points thereon; means on each jaw for holding one half of a split button die; a radial lug on each jaw; a cap provided on its periphery with slots to receive and operatively engage said lugs and arcuately movable relative to said disk for swinging 'said jaws on their pivots to open the same; springs between the disk and cap to normally urge said cap in jawopening direction; a shank; a head thereon and fixed to rotate therewith and supporting said disk; a ring connected to said head and having a lug engaging a notch in the cap for normally restraining said cap from moving in jaw-opening direction, said disk and cap being axially movable away from said head and shank to separate said lug and notch and permit rotation of said cap in jaw-opening direction when said cap and disk are moved axially relative to. said head and shank; and means interconnecting said disk and head including springs to yieldingly hold said disk and cap and head against said axial movement away from said head.

8. A self-opening die holder including a disk; a pair of jaws pivotally mounted on the disk at diametrically opposite points thereon; means on each jaw for holding one half of a split button die; a radial lug on each jaw; a cap provided on its periphery with slots to receive and operatively engage said lugs and arcuately movable relative to said disk for swinging said jaws on their pivots to open the same; springs between the disk and cap to normally urge said cap in jawopening direction; a shank; a head thereon and fixed to rotate therewith and supporting said disk; and a ring connected to said head and having a lug engaging a notch in the cap for normally restraining said cap from moving in jawopening direction, said disk and cap being axially movable away from said head and shank to separate said lug and notch and permit rotation of said cap in jaw-opening direction when said cap and disk are moved axially relative to said head and shank, said cap having a shoulder adjacent said notch to engage said lug and hold said cap in jaw-opening position upon rotation of the cap in jaw-opening direction.

9. A self-opening die-holder comprising a cylindrical housing having a shell slotted at diametrically opposite points; a jaw-carrier; and a pair of die-carrying jaws pivoted for swinging movement thereon and having arms extending through and radially slidable in said housing slots respectively, said jaw-carrier being rotatable relatively to the housing in one direction to move said jaws to close the dies, and in the other direction to open said dies.

10. A self-opening die-holder comprising a cylindrical housing having a shell slotted at diametrically opposite points; a jaw-carrier; a pair of die-carrying jaws pivoted for swinging movement thereon and having arms extending through and radially slidable in said housingslots respectively; means extending through a slot in said shell for partially rotating said jawcarrier relatively to the housing in one direction to swing said jaws to close the dies; and a spring enclosed within the shell for moving said jawcarrier in the other direction to open said dies.

11. A self-opening die-holder comprising a cylindrical housing having a shell slotted at diametrically opposite points; a jaw-carrier; a pair of die-carrying jaws pivoted for swinging movement thereon and having arms extending through and radially slidable in said housingslots respectively; means extending through a slot in said shell for partially rotating said jawcarrier relatively to the housing in one direction to swing said jaws to close the dies; a spring enclosed within the shell for moving said jawcarrier in the other direction to open said dies; means for locking said jaw-carrier in its dieclosing position during the thread-cutting operation; means for releasing said locking means from the jaw-carrier at a predetermined point of said operation and permit said spring toperform its function; and means outside of said shell for adjusting said locking means.

12. A self-opening die comprising a die-jaw carrier; a driver-head coupled thereto for corotation and having a shank; yielding means for normally holding said carrier and head together longitudinally; a sleeve corotatively connected with and slidably supporting said shank; and another yielding means weaker than the first yielding means for normally holding said sleeve and shank against such sliding movement relatively to each other such that the carrier and sleeve are yieldingly urged toward each other under the combined action of both yielding means.

13. A self-opening die comprising a die-jaw car carrier; a driver head coupled thereto for corotation and having a shank; yielding means for normally holding said carrier and head together 1ongitudinally to permit separation of the two parts upon cessation of advance of the driver head; a sleeve corotatively connected with and slidably supporting said shank; and yielding means weaker than the first yielding means for normally holding said sleeve and shank together to permit sliding movement during the threadcutting operation, said means coacting with the first-mentioned yielding means to urge the carrier and sleeve toward each other, and said means causing partial retraction of the carrier quickly upon the release of the dies from the work.

14. A self-opening die-holder including a jawcarrier; a jaw for holding a thread cutter, pivotally mounted on said carrier and having a slide bar; a housing for said jaw-carrier and jaw'having a guiding recess for said slide bar and being movable relatively to said carrier for swinging the said jaws on their pivots to open the same; and resilient means between the housing and the carrier to normally urge said housing in jaw-opening direction.

15. A self-opening die comprising a driver head having a shank; a sleeve corotatively connected with and slidably supporting said shank; a diejaw carrier; means for adjustably securing the river head to the carrier whereby lateral adjustment of the latter relatively to the head is provided for, so that the shank may be made to slide easily within the sleeve during a cut; yielding means for normally holding said carrier and head together longitudinally; and another yielding means weaker than the first yielding means for normally holding said sleeve and shank against such sliding movement relatively to each other so that the carrier and sleeve are yieldingly urged toward each other under the combined action of both means.

16. A self-opening die-holder comprising a cylindrical housing having a shell slotted at diametrically opposite points; a jaw-carrier rotatably' mounted in said housing; a pair of diecarrying jaws pivoted for swinging movement on said jaw-carrier and having arms extending through and radially slidable in said housing slots respectively, so that when the jaw-carrier is rotated relatively to the housing in one direction the jaws will close the dies, and when the carrier is rotated in the other direction the jaws will open the dies; a driver head, having a shank; and means for adjustably securing the driver head to the jaw-carrier whereby lateral adjustmentoi the latter relatively to the head is pro vided for so that said jaw-carrier may be made to rotate easily relatively to the housing during a cut.

GEORGE E. COTE. 

